. u.s. presidentbarackobamaandhis republican challenger, mittromney,debatedtheeconomy, health care, and the role of government. their debate took place in colorado, one of the battleground states that could decide the election next month. nhk world's mami mochizuki reports from denver. >> reporter: this could turn out to be the most scrutinized event in the election. the first televised debate ahead of the november vote. for both candidates, risks are high. >> president obama and governor romney. [ applause ] >> reporter: americans got their first chance to size up the candidates side by side. they've watched the incumbent for four years. barack obama came into office promising to lead a turnaround. but economy growth has been sluggish. still, he leads in a number of polls, but only just. >> the only way to meet governor romney's pledge of not reducing the deficit, or not adding to the deficit, is by burdening middle-class families. now, that's not my analysis. >> reporter: mitt romney has tried to make the case that his business experience prepares him to lead a recovery. but